Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones).
While input devices have found many applications, engineers continue to seek design alternatives that reduce costs and/or improve sensor performance. For example, improvements in efficiently and reliably detecting and locating the presence of input objects in the sensing region.
Specifically, in some input devices situations may arise that can cause one or more objects to be “hallucinated”. That is, the input device may detect and identify the presence of an object in a sensing region where no such object actually exists. Such a hallucination of an object can cause proximity sensor device to generate unwanted input, or incorrectly respond to real input by the user. As such, such a hallucination can seriously impair the usability of the input device and/or the associated electronic system.
Such a hallucination of objects can occur for a variety of reasons. One potential reason is that the input device relied upon deficient baseline values in determining the presence of the object. Specifically, typical input devices compare baseline values to measured values to determine the presence objects. If the baseline values used to determine object presence are incorrect, the device may detect an object where no such object actually exists.
Thus, there remains a continuing need for improvements in the techniques used to detect and identify objects in proximity sensor devices. Other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.